The Taxonomy, Distribution and Variability of the Genus Roemeria Medic. (Papaveraceae)

The genus Roemeria Medic, is recognized to contain two species, R. refracta DC. and R. hybrida (L.) DC. Both these consist of two subspecies, of which R. refracta subsp. occidentalis Kadereit is newly described. A detailed analysis of the geographical distribution of a a number of characters of R. hybrida is presented. This analysis leads to the maintenance of R. hybrida subsp. hybrida and subsp. dodecandra (Forsk.) Maire as two rather variable subspecies of more or less vicarious distribution. Although there exist conspicuous differences in floral, fruit and seed characters between R. refracta and R. hybrida, the two species are regarded as congeneric. This is supported by the behaviour of the fruits after fertilization. In much of the material seen, these turn downwards while developing and, shortly before maturity, up again. The possible adaptive significance of this is. discussed.